Abstract
In this study, efforts were undertaken to produce ultra-high-strength mortars (UHSM) from conventionally available materials. Selection of mixtures and optimization of mixtures were achieved by adopting the basic principles of UHSM and through trial studies. A preliminary investigation was carried out to assess the effects of different curing regimes on the strength development of UHSM. Effects of fiber addition, heat treatment, and preset pressure on the rate of strength development of UHSM mixtures were individually assessed to better understand their benefits in the production of UHSM. Mechanical properties of the heat-treated UHSM were then investigated to determine the performance of the UHSM developed from conventional materials. Results from this study suggested that for the production of UHSM, a multiple curing regime was best suited and was then used for further studies. Data on strength development indicated that heat treatment increased the strengths by 57% to 75%. With application of preset pressure, the compressive strengths of UHSM were increased significantly by 15% to 18%. The optimum quantity of fibers to produce UHSM was found to be 2% to 3%. Effectiveness of fibers in increasing the strength of UHSM was found to be higher for heat-cured specimens than for normal water-cured specimens. The maximum target strengths obtained from the UHSM were 194 MPa, 24 MPa, and 31 MPa for compression, split tension, and flexure, respectively. The UHSM also showed improved energy absorption and toughness characteristics, especially at higher-fiber dosages.
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